DE69909423T2 - Load-dependent low-temperature cooling circuit - Google Patents

Description

technical area

This invention relates generally on the cooling and more specifically on the use of multi-component refrigerants, those for generating cold useful are. The invention is particularly useful for providing cold up down to cryogenic temperatures.

State of the art

cold is conventionally done by compacting and then expanding of a refrigerant within a cooling circuit generated. Well-known examples of such conventional systems include chillers and air conditioners. Typically the refrigerant is a one component fluid, a phase change at a required temperature of liquid going through to gas making its latent heat of vaporization available for cooling purposes becomes. The efficiency of the conventional system can be increased by using a multi-component fluid as the refrigerant can be improved, the variable amounts of cold over one can provide the required temperature range. Indeed can be known Multi-component fluid refrigeration cycles not efficiently cold over you huge Temperature range down to colder cryogenic temperatures provide. About that In addition, most well-known refrigerants are toxic, flammable and / or ozone depleting.

In EP-A-0 516 093 there is a cooling unit described a high temperature side refrigerant circuit and a Low-temperature side refrigerant circuit to train an independent closed refrigerant circuit has a cooling effect provided by refrigerant discharged from a compressor condensed and then is evaporated, and an evaporator of the high temperature side refrigerant circuit and forms the condenser of the low temperature side refrigerant circuit a heat exchanger out. The unit uses a non-acetropic mixed refrigerant, which is an inorganic selected from the group consisting of argon and nitrogen Refrigerant a hydrocarbon and at least one of hydrochlorofluorocarbon, Hydrofluorocarbon hydrocarbon and fluorocarbon selected group refrigerant having.

Substitute for chlorodifluoromethane (HCFC-22) are disclosed in US-A-5 736 063.

Accordingly, there is a task of this invention in providing a method of producing of cold using a multi-component refrigerant, the cold over a large temperature range can provide down to cryogenic temperatures.

Another object of this invention consists in the provision of a multi-component refrigerant, that is non-toxic, non-flammable, and low or non-ozone depleting is.

Summary of the invention

The above and other tasks, which will become apparent to those skilled in the art from this description solved by the present invention, one aspect of which Process for generating cold according to claim 1 is.

Another aspect of the invention is a mixture of refrigerants according to claim 5th

As used here, the Term "refrigerant with variable load " Mixture of two or more components in proportions so that the liquid phase of these components a continuous and increasing temperature change between the bubble point and the dew point of the mixture. The The bubble point of the mixture is the temperature at one given pressure at which the mixture is completely in the liquid phase is present, but an addition of warmth the formation of a vapor phase in equilibrium with the liquid phase triggers. The dew point of the mixture is that temperature for a given Pressure at which the mixture is completely in the vapor phase, however an extraction of heat the formation of a liquid phase in equilibrium with the vapor phase triggers. Thus, the temperature range is between the bubble point and the dew point of the mixture is the area in which both liquid how vapor phases coexist in equilibrium. In practice this Ending are the temperature differences between the bubble point and the dew point for the refrigerant with variable load at least 10 ° K, preferably at least 20 ° K and most preferably at least 50 ° K.

As used herein, the term "fluorocarbon" denotes one of the following: tetrafluoromethane (CF ₄ ), perfluoroethane (C ₂ F ₆ ), perfluoropropane (C ₃ F ₈ ), perfluorobutane (C ₄ F ₁₀ ), perfluoropentane (C ₅ F ₁₂ ), Perfluoroethene (C ₂ F ₄ ), perfluoropropene (C ₃ F ₆ ), perfluorobutene (C ₄ F ₈ ), perfluoropentene (C ₅ F ₁₀ ), hexafluorocyclopropane (cyclo-C ₃ F ₆ ) and octafluorocyclobutane (cyclo-C ₄ F ₈ ).

As used herein, the term "hydrofluorocarbon" means one of the following: Fluoroform (CHF ₃ ), pentafluoroethane (C ₂ HF ₅ ), tetrafluoroethane (C ₂ H ₂ F ₄ ), heptafluoropropane (C ₃ HF ₇ ), hexafluoropropane (C ₃ H ₂ F ₆ ), pentafluoropropane (C ₃ H ₃ F ₅ ), Tetrafluoropropane (C ₃ H ₄ F ₄ ), nonafluorobutane (C ₄ HF ₉ ), octafluorobutane (C ₄ H ₂ F ₈ ), undecafluoropentane (C ₅ HF ₁₁ ), methyl fluoride (CH ₃ F), difluoromethane (CH ₂ F ₂ ), ethyl fluoride (C ₂ H ₅ F), difluoroethane (C ₂ H ₄ F ₂ ), trifluoroethane (C ₂ H ₃ F ₃ ), difluoroethene (C ₂ H ₂ F ₂ ), trifluoroethene (C ₂ HF ₃ ), Fluoroethene (C ₂ H ₃ F), pentafluoropropene (C ₃ HF ₅ ), tetrafluoropropene (C ₃ H ₂ F ₄ ), trifluoropropene (C ₃ H ₃ F ₃ ), difluoropropene (C ₃ H ₄ F ₂ ), heptafluorobutene (C ₄ HF ₇ ), hexafluorobutene (C ₄ H ₂ F ₆ ) and nonafluoropentene (C ₅ HF ₉ ).

As used herein, the term "hydrochlorofluorocarbon" denotes one of the following: chlorodifluoromethane (CHClF ₂ ), chlorofluoromethane (CH ₂ ClF), chloromethane (CH ₃ Cl), dichlorofluoromethane (CHCl ₂ F), chlorotetrafluoroethane (C ₂ HClF ₄ ), chlorotrifluoroethane (C ₂ H ₂ ClF ₃ ), chlorodifluoroethane (C ₂ H ₃ ClF ₂ ), chlorofluoroethane (C ₂ H ₄ ClF), chloroethane (C ₂ H ₅ Cl), dichlorotrifluoroethane (C ₂ HCl ₂ F ₃ ), dichlorodifluoroethane (C ₂ H ₂ Cl ₂ F ₂ ), dichlorofluoroethane (C ₂ H ₃ Cl ₂ F), dichloroethane (C ₂ H ₄ Cl ₂ ), trichlorofluoroethane (C ₂ H ₂ Cl ₃ F), trichlorodifluoroethane (C ₂ HCl ₃ F ₂ ) , Trifluoroethane (C ₂ H ₃ Cl ₃ ), tetrachlorofluoroethane (C ₂ HCl ₄ F), chloroethene (C ₂ H ₃ Cl ₂ ), difluoroethene (C ₂ H ₂ Cl ₂ ), dichlorofluoroethene (C ₂ H ₂ ClF) and dichlorodifluoroethene (C ₂ HClF ₂ ).

As used herein, the term "fluoroether" means one of the following: trifluoromethyoxyperfluoromethane (CF ₃ -O-CF ₃ ), difluoromethoxy-perfluoromethane (CHF ₂ -O-CF ₃ ), fluoromethoxy-perfluoromethane (CH ₂ FO-CF ₃ ) , Difluoromethoxy-difluoromethane (CHF ₂ -O-CHF ₂ ), difluoromethoxy-perfluoroethane (CHF ₂ -OC ₂ F ₅ ), difluoromethoxy-1,2,2,2-tetrafluoroethane (CHF ₂ -OC ₂ HF ₄ ), difluoromethoxy- 1,1,2,2-tetrafluoroethane (CHF ₂ -OC ₂ HF ₄ ), perfluoroethoxyfluoromethane (C ₂ F ₅ -O-CH ₂ F), perfluoro-methoxy-1,1,2-trifluoroethane (CF ₃ -OC ₂ H ₂ F ₃ ), perfluoromethoxy-1,2,2-trifluoroethane (CF ₃ OC ₂ H ₂ F ₃ ), cyclo-1,1,2,2-tetrafluoropropyl ether (cyclo-C ₃ H ₂ F ₄ -O-) , Cyclo-1,1,3,3-tetrafluoropropyl ether (cyclo-C ₃ H ₂ F ₄ -O-), perfluoromethoxy-, 1,1,2,2-tetrafluoroethane (CF ₃ -OC ₂ HF ₄ ), cyclo- 1,1,2,3,3-pentafluoropropyl ether (cycloC ₃ H ₅ -O-), perfluoromethoxy-perfluoroacetone (CF ₃ -O-CF ₂ -O-CF ₃ ), perfluomethoxy-perfluoroethane (CF ₃ -OC ₂ F ₅ ), Perfluoromethoxy-1,2,2,2-tetrafluoroethane (CF ₃ -O C ₂ HF ₄ ), perfluoromethoxy-2,2,2-trifluoroethane (CF ₃ -OC ₂ H ₂ F ₃ ), cyclo-perfluoromethoxy-perfluoroacetone (cyclo-CF ₂ -O-CF ₂ -O-CF ₂ -) and Cyclo-perfluoropropyl ether (cycloC ₃ F ₆ -O).

As used herein, the term "atmospheric gas" means one of the following: nitrogen (N ₂ ), argon (Ar), krypton (Kr), xenon (Xe), neon (Ne), carbon dioxide (CO ₂ ), oxygen (O ₂ ) and helium (He).

As used herein, the term "hydrocarbon" refers to one of the following: hydrogen (H ₂ ), methane (CH ₄ ), ethane (C ₂ H ₆ ), ethene (C ₂ H ₄ ), propane (C ₃ H ₈ ), Propene (C ₃ H ₆ ), butane (C ₄ H ₁₀ ), butene (C ₄ H ₈ ), cyclopropane (C ₃ H ₆ ) and cyclobutane (C ₄ H ₈ ).

As used here, the Term "non-toxic" the nonexistent Risk of an acute or constant Health risks in handling a substance within acceptable Exposure limits.

As used here, the The term "non-flammable" means none or a very high flash point of at least 600 ° K.

As used herein, the term "low ozone depleting" means an ozone depleting potential of less than 0.15 according to the Montreal Protocol Convention, where dichlorofluoromethane (CCl ₂ F ₂ ) has an ozone depleting potential of 1.0.

As used here, the Term "non ozone depleting" that no component is present, which has a chlorine, bromine or iodine atom.

As used herein, the term "normal boiling point" refers to the boiling temperature at 1 standard atmospheric pressure, ie 14.696 pounds per inch ² absolute.

As used here, the Term "cryogenic Temperature "a Temperature of 150 ° K Or less.

As used here, the Term "indirect Heat exchange "the spending of two fluids in a heat exchange relationship without any physical contact or mixing of the fluids together.

As used here, the Term "expansion" the effect of a Pressure reduction.

As used here, denote the Terms "Turboexpansion" and "Turboexpander" a process or a device for the flow of high pressure fluid through a turbine to the pressure and reduce the temperature of the fluid, thereby creating cold becomes.

Short description of the drawings

1 Fig. 3 is a generalized graph of temperature versus concentration for a mixed load refrigerant mixture at a given pressure.

2 Figure 3 is a schematic illustration of a system in which the invention is applicable.

3 Figure 3 is a schematic representation of another system in which the invention is applicable.

4 Figure 3 is a schematic illustration of a three-loop system in which the invention can be used to provide cold over a wide temperature range.

Full description

The invention has a refrigerant mixture composed of defined components in certain proportions, which forms a refrigerant mixture with a variable load, and the use of such a refrigerant mixture in a cooling cycle. The variable load refrigerant mixture can be in all gas, gas-liquid or liquid phases depending on the process and the location in the process, ie the heat exchange point (top, center, bottom). The cycle is preferably a closed-loop cycle. The refrigerant mixture with variable load shows a smooth temperature change that accompanies a phase change. This is in 1 demonstrated that is a graph of temperature versus concentration of a mixed load refrigerant mixture at a given pressure. For any given mixture of components A and B (xmix) at one temperature (tmix) there are two phases, the composition of the saturated vapor (xmixv) differs from that of the liquid in equilibrium with the vapor, and the liquid has the composition (xmixl) on. When the temperature is reduced, both the liquid phase composition and the vapor phase composition change, both of which are enriched in component B. The condensing mixture constantly changes its composition and therefore its condensation temperature. This feature enables the effectiveness of a cooling cycle to be improved. The cycle improvement relates to the use of several components, each with its own normal boiling point and an associated latent heat of vaporization. The appropriate selection of refrigerant components and the optimal concentrations in the mixture, together with operating pressure levels and refrigerant cycles, enable the generation of variable amounts of cold over the required temperature range. Providing variable cooling as a function of temperature enables optimal control of heat exchange temperature differences within the user cooling system, thereby reducing system energy requirements.

The refrigerant mixture with variable Last of this invention features at least one component from the Fluorocarbons, hydrofluorocarbons and fluoroethers existing group and at least one component from the group consisting of fluorocarbons, Hydrofluorocarbons, fluoroethers and atmospheric Gases existing group on.

A preferred refrigerant mixture with variable Load of this invention has at least two components from the from fluorocarbons, hydrofluorocarbons and Fluorether existing group and at least one component made of fluorocarbons, hydrofluorocarbons, Fluoroethers, and atmospheric Gases existing group on.

Another preferred refrigerant mixture with variable load of this invention has at least one fluorocarbon and at least one component from that of hydrofluorocarbons and atmospheric Gases existing group on.

Another preferred refrigerant mixture variable load of this invention has at least one fluorocarbon, at least one hydrofluorocarbon and at least one atmospheric Gas on.

Another preferred refrigerant mixture with variable load of this invention has at least three components from that of fluorocarbons, hydrofluorocarbons and fluoroethers existing group and at least one component made from fluorocarbons, hydrofluorocarbons, Fluoroethers and atmospheric Gases existing group on.

Another preferred refrigerant mixture with variable load of this invention has at least two components from that of fluorocarbons, hydrofluorocarbons and fluoroethers existing group and at least one atmospheric Gas on.

Another preferred refrigerant mixture with variable load of this invention has at least two components from that of fluorocarbons, hydrofluorocarbons and fluoroethers existing group, at least one atmospheric Gas and at least one component made from fluorocarbons, Hydrofluorocarbons, fluoroethers and atmospheric Gases existing group on.

Another preferred refrigerant mixture with variable load of this invention has at least two components from that of fluorocarbons, hydrofluorocarbons and fluoroethers existing group and at least two different atmospheric Gases on.

Another preferred refrigerant mixture variable load of this invention includes at least one fluoroether, i.e. it has at least one fluoroether and at least one component made from fluorocarbons, hydrofluorocarbons, Fluoroethers and atmospheric Gases existing group on.

The variable load refrigerant contains neither hydrochlorofluorocarbons nor hydrocarbons. Most preferably, the variable load refrigerant is non-toxic, non-flammable, and non-ozone depleting, and each component of the variable load refrigerant mixture is either a fluorine hydrocarbon a hydrofluorocarbon a fluoroether or an atmospheric gas.

In a preferred embodiment the refrigerant of the invention with variable load only from fluorocarbons. In another preferred embodiment the refrigerant of the invention with variable load only from fluorocarbons and hydrofluorocarbons. In a further preferred embodiment of the invention the refrigerant with variable load only from fluorocarbons and atmospheric gases. In another preferred embodiment the refrigerant of the invention with variable load only from fluorocarbons, hydrofluorocarbons and Fluoroethers. In yet another preferred embodiment the refrigerant of the invention with variable load only from fluorocarbons, fluoroethers and atmospheric Gases. Most preferred is each component of the refrigerant with variable load either a fluorocarbon, a hydrofluorocarbon, a fluoroether or an atmospheric gas.

The invention is particularly advantageous applicable to efficiently starting cryogenic temperatures of reaching ambient temperatures. Tables 1-14 list preferred ones Examples of refrigerant mixtures with variable load of this invention. The given in the tables Concentration ranges are in mol%. The ones shown in Tables 1-5 Examples are preferred mixtures for generating cold over about 200 ° K and those in Tables 6-14 Examples shown are preferred mixtures for generating cold under about 200 ° K.

Table 1 component concentration range C ₅ F ₁₂ 5-35 C ₄ F ₁₀ 0-25 C ₃ F ₈ 10-50 C ₂ F ₆ 10-60 CF ₄ 0-25

Table 2 component concentration range C ₅ F ₁₂ 5-35 C ₃ H ₃ F ₆ 0-25 C ₃ F ₈ 10-50 CHF ₃ 10-60 CF ₄ 0-25

Table 3 component concentration range C ₃ H ₃ F ₅ 5-35 C ₃ H ₃ F ₆ 0-25 C ₂ H ₂ F ₄ 5-20 C ₂ HF ₅ 5-20 C ₂ F ₆ 10-60 CF ₄ 0-25

Table 4 component concentration range CHF ₂ -OC ₂ HF ₄ 5-35 C ₄ F ₁₀ 0-25 CF ₃ -O-CHF ₂ 10-25 CF ₃ -O-CF ₃ 0-20 C ₂ F ₆ 10-60 CF ₄ 0-25

Table 5 component concentration range CHF ₂ -OC ₂ HF ₄ 5-35 C ₃ H ₂ F ₆ 0-25 CF ₃ -O-CHF ₂ 10-50 CHF ₃ 10-60 CF ₄ 0-25

Table 6 component concentration range C ₅ F ₁₂ 5-25 C ₄ F ₁₀ 0-15 C ₃ F ₈ 10-40 C ₂ F ₆ 0-30 CF ₄ 10-50 Ar 0-40 N ₂ 10-80

Table 7 component concentration range C ₃ H ₃ F ₅ 5-25 C ₄ F ₁₀ 0-15 C ₃ F ₈ 10-40 CHF ₃ 0-30 CF ₄ 10-50 Ar 0-40 N ₂ 10-80

Table 8 component concentration range C ₃ H ₃ F ₅ 5-25 C ₃ H ₃ F ₆ 0-15 C ₂ H ₂ F ₄ 0-20 C ₂ HF ₅ 5-20 C ₂ F ₆ 0-30 CF ₄ 10-50 Ar 0-40 N ₂ 10-80

Table 9 component concentration range C ₃ H ₃ F ₅ 5-25 C ₃ H ₂ F ₆ 0-15 CF ₃ -O-CHF ₂ 10-40 CHF ₃ 0-30 CF4 0-25 Ar 0-40 N ₂ 10-80

Table 10 component concentration range C ₅ F ₁₂ 5-25 C ₄ F ₁₀ 0-15 C ₃ F ₈ 10-40 C ₂ F ₆ 0-30 CF ₄ 10-50 Ar 0-40 N ₂ 10-80 ne 0-10 He 0-10

Table 11 component concentration range C ₃ H ₃ F ₅ 5-25 C ₄ F ₁₀ 0-15 C ₃ F ₈ 10-40 CHF ₃ 0-30 CF ₄ 10-50 Ar 0-40 N ₂ 10-80 ne 0-10 He 0-10

Table 12 component concentration range C ₃ H ₃ F ₅ 5-25 C ₃ H ₂ F ₆ 0-15 C ₂ H ₂ F ₄ 5-20 C ₂ HF ₅ 5-20 C ₂ F ₆ 0-30 CF ₄ 10-50 Ar 0-40 N ₂ 10-80 ne 0-10 He 0-10

Table 13 component concentration range CHF ₂ -OC ₂ HF ₄ 5-25 C ₄ F ₁₀ 0-15 CF ₃ -O-CHF ₂ 10-40 CF ₃ -O-CF ₃ 0-20 C ₂ F ₆ 0-30 CF ₄ 10-50 Ar 0-40 N ₂ 10-80 ne 0-10 He 0-10

Table 14 component concentration range C ₃ H ₃ F ₅ 5-25 C ₃ H ₂ F ₆ 0-15 CF ₃ -O-CHF ₃ 10-40 CHF ₃ 0-30 CF ₄ 0 - 25 Ar 0-40 N ₂ 10-80 ne 0-10 He 0-10

2 illustrates a cooling cycle in which the invention can be applied. Now on the 2 Referring to the variable load refrigerant mixture of this invention, in a refrigeration cycle or loop 1 circulated. A refrigerant 2 is by passing through a compressor 3 to form a compressed refrigerant fluid 4 compressed by passing it through an aftercooler 70 cooled to near ambient temperature, and then cooled and preferably at least partially by passing it through a heat exchanger 5 liquefied. Unless otherwise stated, each heat exchange step illustrated in the drawings is an indirect heat exchange step. After that, a refrigerant is refrigerated 6 throttled, ie by a valve 7 expanded to a lower pressure. Pressure expansion can be accomplished by a turbine such as gas expansion, a two-phase expansion, or a liquid expansion turbine. The cold generated can be used at a single or narrow temperature level by a fluid 8th through indirect heat exchange in a heat exchanger 9 is cooled, or it can be in the heat exchanger 5 can be used over a much wider temperature range. The cold can be used to cool one or more fluid flows through the heat exchanger 5 run as if through a current in a countercurrent 10 and in a direct current 11 shown. Although it is presented on an overall basis that the current 11 in the heat exchanger 5 is heated, it can be on a local basis within the heat exchanger 5 be cooled. Subsequently, the resulting heated refrigerant mixture is called the stream 2 to the compressor 3 and the cycle repeats itself.

The cooling arrangement could also have a pre-cooler circuit or loop 12 include where a refrigerant mixture with variable load designed to provide cold at intermediate temperature levels 13 of this invention in a pre-cooler compressor 14 compressed, in an aftercooler 71 cooled to ambient temperature, and a resulting compressed fluid 15 in the heat exchanger 5 is cooled. The resulting chilled fluid 16 is through a valve or a suitable turbine 17 throttled to produce cold and a resulting refrigerant 18 with lower temperature is heated and then as the current 13 to the compressor 14 circulated.

The effect of the pre-cooler loop can be achieved by intermediate removal of part of the refrigerant mixture and recycling of liquid as in 3 shown to be accomplished. The liquid recirculation feature provides process flexibility because the refrigerant blends are adjusted to the required temperature ranges and unnecessary cooling and potential freezing of the liquid refrigerant are avoided. The reference numerals in 3 are the same for the general elements as those in 2 and these elements will not be described in detail again. Now on the 3 A refrigerant is used 20 by passing through a compressor 21 to form a compressed refrigerant 22 compressed by an aftercooler 71 cooled from the compression heat to near ambient temperature and then through a partial passage through the heat exchanger 5 is further cooled and partially condensed. A refrigerated two-phase refrigerant mixture 23 becomes a phase separator 24 fed where it is separated into vapor and liquid. A steam 25 is through the heat exchanger 5 further cooled, through a valve 26 throttled and by passing through the heat exchanger 9 and / or 5 heated. A liquid 27 is through a valve 28 guided and then by passing through the heat exchanger 5 evaporated. In the in the 3 In the illustrated embodiment, the liquid is combined with the lower pressure vapor passing through the valve 26 was throttled before evaporation. The resulting heated refrigerant mixture is then called a stream 29 to the compressor 21 returned and the cooling cycle starts again. Although single-phase separation is illustrated, it is understood that multi-phase separations at different temperature levels could also be used to provide graded pre-cooling circuits.

The invention is particularly useful about cold starting from ambient temperature down to a cryogenic To provide temperature, the level of which is down to 5 ° K can. Although the invention provides such coldness over this used throughout the temperature range in a single loop it is generally preferred to use this cold in one To provide a plurality of cascade loops. The use of several Cascade grinding enables it that every cycle cold over one chosen Can provide temperature range. This will make choosing one suitable refrigerant mixture relieved because the selected Mix only over be operational over a limited temperature range got to. It should be noted that although each cascade cycle is intended to be cold primarily about its own should provide assigned temperature range, he also some cold at higher Can provide temperature levels. Therefore, the cascade circuits can Regarding the provision of cold at a given temperature range overlap somewhat with each other.

The cascade loop system is related to 4 illustrated and explained. Now on the 4 For reference, a refrigerant with a variable load intended for higher temperatures has two or more substances from, for example, tetrafluoromethane, fluoroform, perfluoropropane, perfluorobutane, pentafluoropropane, tetrafluoroethane, difluoromethoxy difluoromethane and perfluoropentane, and is circulated in a loop at a higher temperature 30 in which Cold is provided from the ambient temperature of about 300 ° K down to about 200 ° K. The approximately 300 ° K warm refrigerant 31 for higher temperature is in a compressor 32 compressed by a cooler 33 and a heat exchanger 60 cooled and through a valve 34 throttled to refrigerant 35 for a lower temperature at about 200 ° K. The refrigerant is then heated back to a lower temperature to about 300 ° K and as the current 31 to the compressor 32 recycled.

Intermediate temperature refrigerant with variable load, which may contain nitrogen and / or argon in addition to one or more of the components mentioned for the fluid for higher temperature, is in an intermediate temperature loop 40 circulates in which cold from about 200 ° K to about 100 ° K is provided. A refrigerant 41 for intermediate temperature is in a compressor 42 compressed by a cooler 43 and the heat exchangers 60 and 61 cooled and through a valve 44 throttled to refrigerant 45 for lower temperature to generate at about 100 ° K, which is heated and then as a stream 41 to the compressor 42 is returned.

Very low temperature refrigerant contains two or more substances from nitrogen, argon, helium, neon and hydrogen and is looped 50 for very low temperatures, in which the temperature level is reduced from about 100 ° K to about 20 ° K or even less. The refrigerant 51 for very low temperature is in a compressor 52 compressed by a cooler 53 and the heat exchangers 60 . 61 and 62 cooled, and through a valve 54 throttled to refrigerant 55 for lower temperature at about 20 ° K or lower, which is by passing through a heater 56 and the heat exchangers 62 . 61 and 60 warmed up and then as a stream 51 to the compressor 52 is returned.

The invention is for deployment from cold over one huge Temperature range and in particular over a temperature range particularly useful throughout which includes cryogenic temperatures. In a preferred embodiment The invention has each of the two or more components of the refrigerant mixture with a variable load to a normal boiling point that is at least 20 ° Kelvin from the normal boiling point of every other component in this refrigerant mixture different. This increases the effectiveness a provision of cold over one huge Temperature range and in particular over a temperature range away, which includes cryogenic temperatures. In a particularly preferred one embodiment the invention is the normal boiling point of the highest boiling Component of the multi-component refrigerant by at least 100 ° K and most preferably at least 200 ° K higher than the normal boiling point the lowest boiling component of the multi-component refrigerant.

The components and their concentrations, which is the refrigerant mixture of this invention are such that they are a Refrigerant mixture train with variable load and such a variable Load characteristic preferably over the entire temperature range of the process of the invention maintained. This increases the efficiency with which the cold generated and over such a big one Temperature range can be used clearly. The set one Group of components has the added benefit that they can be used to form mixtures that are not toxic, not are flammable and low or non-ozone depleting. This offers other advantages over conventional refrigerants, which are typically toxic, flammable and / or ozone depleting are.

A preferred variable load refrigerant mixture of this invention that is non-toxic, non-flammable, and non-ozone depleting has two or more components from the one of C ₅ F ₁₂ , CHF ₂ -OC ₂ HF ₄ , C ₄ HF ₉ , C ₃ H ₃ F ₅ , C ₂ F ₅ -O-CH ₂ F, C ₃ H ₂ F ₆ , CHF ₂ -O-CHF ₂ , C ₄ F ₁₀ , CF ₃ -OC ₂ H ₂ F ₃ , C ₃ HF ₇ ; CH ₂ FO-CF ₃ , C ₂ H ₂ F ₄ , CHF ₂ -O-CF ₃ , C ₃ F ₈ , C ₂ HF ₅ , CF ₃ -O-CF ₃ , C ₂ F ₆ , CHF ₃ , CF ₄ , O ₂ , Ar, N ₂ , Ne and He existing group.

The invention can be used to generate cold for one size Number of uses and especially used for cryogenic applications become. The following can be cited under such uses: Gas separation processes such as cryogenic air separation and other cryogenic Separations, natural gas processing, liquefier, food freezing, Vent gas recovery, Pumping heat, Storage of cryogenic liquids and recondensation of transport containers, crystallization, solidification, Low temperature milling, chemical storage and transportation, storage and transportation of biological and medical material and refrigerated spaces, i.e. for the Handling and storage of materials used cold rooms.

Claims (9)

Process for generating cold, the process of which: (A) a refrigerant mixture is compressed with a variable load to a compressed refrigerant mixture generate with variable load, the mixture at least one Component made of fluorocarbons, hydrofluorocarbons and fluoroethers existing group and at least one component made from fluorocarbons, hydrofluorocarbons, Fluoroethers and atmospheric Contains gases existing group the components being different, the refrigerant mixture neither hydrocarbons nor hydrochlorofluorocarbons contains and being the normal boiling point of the highest boiling component of the refrigerant mixture at least by 100 ° K is higher than the normal boiling point of the lowest boiling component of the refrigerant mixture; (B) the compressed refrigerant mixture cooled with variable load is a chilled, compressed refrigerant mixture generate with variable load; (C) the cooled, compressed refrigerant mixture is expanded with variable load and cold is generated to a cooler refrigerant mixture generate with variable load; and (D) the cooler refrigerant mixture heated with variable load becomes. The method of claim 1, wherein the compressed Refrigerant mixture with variable load as a result of the cooling of step (B) partially is condensed and the resulting liquid and residual vapor are separated and the steam before heating then chilled further becomes. The method of claim 1, wherein the method first with a first refrigerant mixture with variable load and then with a second refrigerant mixture with variable Load executed the first refrigerant mixture with variable load by cooling of the second refrigerant mixture is heated with a variable load. The method of claim 1, wherein in step (C) the cooler Refrigerant mixture is generated with a variable load at a cryogenic temperature. Refrigerant mixture, which is non-toxic and not - flammable and causes little ozone depletion and at least a component from that of fluorocarbons, hydrofluorocarbons and fluoroethers existing group and at least one component made from fluorocarbons, hydrofluorocarbons, Fluoroethers and atmospheric Gases existing group, the components being different and the refrigerant mixture has neither hydrocarbons nor hydrochlorofluorohydrocarbons and being the normal boiling point of the highest boiling component of the refrigerant mixture by at least 100 ° K is higher than the normal boiling point of the lowest boiling component of the refrigerant mixture. Refrigerant mixture according to claim 5, each of the components of the mixture having a normal boiling point which is at least 20 ° K from the normal boiling point distinguishes each of the other components of the refrigerant mixture. Refrigerant mixture according to claim 5, the refrigerant mixture at least one fluorocarbon at least one hydrofluorocarbon and at least one atmospheric Has gas. Refrigerant mixture according to claim 5, the refrigerant mixture at least two components made of fluorocarbons, Hydrofluorocarbons and fluoroethers existing group and at least two atmospheric Has gases. Refrigerant mixture according to claim 5, the refrigerant mixture at least one fluoroether and at least one component from the from fluorocarbons, hydrofluorocarbons, fluoroethers and atmospheric Gases existing group.